1. Field of the Invention
The present invention relates to an electrical apparatus of the type having at least one first component arranged within a high-frequency shielded room (or chamber or cubicle), and at least one second component arranged outside the high-frequency shielded room, and having a control computer which is connected to the components via control lines.
2. Description of the Prior Art
An electrical apparatus of the above type in the form of a diagnostic magnetic resonance device is described in overview in the book "Bildgebene Systems for die Medizinische Diagnostik," (Heinz Morneburg. pub.; 3, edition, 1995, Publicis MCD Veriag: pp 501-503). Roughly divided, the magnetic resonance device includes components which are arranged inside a high-frequency shielded room and components which are arranged outside the high-frequency shielded room. The diagnostic magnetic resonance device is controlled by a control computer arranged outside the high-frequency screening cabin. Control of the components arranged outside the screening cabin therein ensues via a central bus. To avoid disturbances in the operation of the magnetic resonance device, the components arranged inside the high-frequency shielded room are either powered with control signals via light waveguides or are turned off during a measuring sequence. Heretofore, the light radially from the control computer to the individual components in the high-frequency shielded room. This placement is costly and complex. In addition, besides being loaded by making the individual control signals, available the control computer is loaded by the communication with the individual components.
Known techniques in the data processing field for relieving a control computer of communications tasks, which employ extra or subsidiary electrical data exchange lines, cannot be used here, since any feeding of electrical data lines into the high-frequency shielded room would disturb the highly sensitive magnetic resonance measurement. Filtering and shielding of such a data bus would be costly and would severely limit the data transmission rate.
German OS 196 25 997 discloses CAN bus (Controller Area Network bus) for driving elements of a machine with at least one bus coupling element, to which a device can be connected by means of an optical transmission path. The data transmission with the optical transmission path assures a simple, reliable, and rapid adjustment or shifting of the respective elements of the machine. Instead of peripheral devices connected to the CAN bus, nodes can be provided--preferably stellar nodes--from which a number of light guides in turn lead to other stellar nodes and/or peripheral devices.
German OS 196 16 753 discloses a device and a method for controlling a data transmission channel or data bus over which data are transmitted according to a prescribe transmission protocol or bus protocol in a bit-serial fashion, e.g. a CAN bus.
Shielded rooms for high-frequency magnetic fields, particularly for NMR tomography systems in medical technology, are described in German PS 38 09 323, and German Utility Model G 90 17 344.9, for example.